Show dialog if exceptions raised before playback begins

corrscope/gui/__init__.py

@@ -377,6 +377,7 @@ class MainWindow(qw.QMainWindow):
     def play_thread(
         self, outputs: List[IOutputConfig], dlg: Optional["CorrProgressDialog"]
     ):
+        try:
             assert self.model
 
             arg = self._get_args(outputs)
@@ -397,6 +398,8 @@ class MainWindow(qw.QMainWindow):
             t.error.connect(self.on_play_thread_error)
             t.ffmpeg_missing.connect(self.on_play_thread_ffmpeg_missing)
             t.start()
+        except Exception as e:
+            TracebackDialog(self).showMessage(format_stack_trace(e))
 
     def _get_args(self, outputs: List[IOutputConfig]):
         arg = Arguments(cfg_dir=self.cfg_dir, outputs=outputs)
@@ -444,6 +447,14 @@ class MainWindow(qw.QMainWindow):
         return self.model.cfg
 
 
+def format_stack_trace(e):
+    if isinstance(e, CorrError):
+        stack_trace = traceback.format_exc(limit=0)
+    else:
+        stack_trace = traceback.format_exc()
+    return stack_trace
+
+
 class CorrThread(qc.QThread):
     is_aborted: Locked[bool]
 
@@ -472,10 +483,7 @@ class CorrThread(qc.QThread):
 
         except Exception as e:
             arg.on_end()
-            if isinstance(e, CorrError):
+            stack_trace = format_stack_trace(e)
-                stack_trace = traceback.format_exc(limit=0)
-            else:
-                stack_trace = traceback.format_exc()
             self.error.emit(stack_trace)
 
         else: